with \(\sigma _{ij}=Cov\left( \hat{R}_{i},\hat{R}_{j}\right) =\frac{1}{2}\left\langle \hat{R}_{i}\hat{R}_{j}+\hat{R}_{j}\hat{R}_{i}\right\rangle -\left\langle \hat{R}_{i}\right\rangle \left\langle \hat{R}_{j}\right\rangle \) , \(i,j=1,2,3,4\) , where \(\hat{R}=(\hat{x}_{A},\hat{p}_{A},\hat{x}_{B},\hat{p}_{B})^{T}\)  is a vector composed by the amplitude and phase quadratures of
bipartite optical beams [1]}. Thus the TMSS covariance matrix can
be partially expressed as (the cross correlations between different
quadratures of one mode are taken as 0)
\(\sigma =\left[\begin{array}{cccc}\bigtriangleup ^{2}\hat{x}_{A} & 0 & Cov\left( \hat{x}_{A},\hat{x}_{B}\right) & 0 \\0 & \bigtriangleup ^{2}\hat{p}_{A} & 0 & Cov\left( \hat{p}_{A},\hat{p}_{B}\right) \\Cov\left( \hat{x}_{A},\hat{x}_{B}\right) & 0 & \bigtriangleup ^{2}\hat{x}_{B} & 0 \\0 & Cov\left( \hat{p}_{A},\hat{p}_{B}\right) & 0 & \bigtriangleup ^{2}\hat{p}_{B}\end{array}\right] .\) 
